Efficient Methods for Point Matching with Known Camera Orientation

Abstract

The vast majority of methods that successfully recover 3D structure from 2D images hinge on a preliminary identification of corresponding feature points. When the images capture close views, e.g., in a video sequence, corresponding points can be found by using local pattern matching methods. However, to better constrain the 3D inference problem, the views must be far apart, leading to challenging point matching problems. In the recent past, researchers have then dealt with the combinatorial explosion that arises when searching among N! possible ways of matching N points. In this paper we overcome this search by making use of prior knowledge that is available in many situations: the orientation of the camera. This knowledge enables us to derive $\mathcal{O}(N^2)$ algorithms to compute point correspondences. We prove that our approach computes the correct solution when dealing with noiseless data and derive an heuristic that results robust to the measurement noise and the uncertainty in prior knowledge. Although we model the camera using orthography, our experiments illustrate that our method is able to deal with violations, including the perspective effects of general real images.

J. Mota is also affiliated with the Dep. of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh PA, USA. This work was partially supported by Fundação para a Ciência e Tecnologia, under ISR/IST plurianual funding (POSC program, FEDER), grant MODI-PTDC/EEA-ACR/72201/2006, and grant SFRH/BD/33520/2008 (CMU-Portugal program, ICTI).